[Keymap] Custom user keymap for Think6.5 with LED range control (#7603)

[Keymap] Custom user keymap for Think6.5 with LED range control (#7603)

* ISO layout for the soldered Think6.5 PCB

* Think6.5 personal layout readme

* Add personal Think6.5 user map with LED group cycling

* Add default case to process_record_user

* Make the ASCII diagram match the layer properly

* Relocate KC_NUHS to the home row for consistency

* Add LAYOUT_65_iso_badge to info.json

* Wire up the badge LEDs as capslock LEDs

* Remove unused keymap variable